WO2018047971A1

WO2018047971A1 - Precoated fin material and heat exchanger using same

Info

Publication number: WO2018047971A1
Application number: PCT/JP2017/032783
Authority: WO
Inventors: 幸平塩見; 涼子藤村; 貴彦水田
Original assignee: 株式会社Uacj
Priority date: 2016-09-12
Filing date: 2017-09-12
Publication date: 2018-03-15
Also published as: JP2018044694A

Abstract

Provided are: a precoated fin material with which a heat exchanger can be produced, said heat exchanger having superior hydrophilic stability of the fins, superior bonding properties, and enabling bonding between fins and aluminum tubing without separately supplying a brazing material; and a heat exchanger that uses the precoated fin material. A precoated fin material (1) comprising an aluminum alloy sheet (11) and a coating film (12) formed on the surface of the aluminum alloy sheet (11), and a heat exchanger using the precoated fin material (1). The aluminum alloy sheet (11) comprises chemical components that contain 1-5 mass% of Si, with the remainder comprising Al and unavoidable impurities. The Si content in the coating film (12) is 10-300 mg/m².

Description

Pre-coated fin material and heat exchanger using the same

The present invention relates to a pre-coated fin material having, for example, an aluminum alloy plate and a coating film, and a heat exchanger using the same.

Generally, an all-aluminum heat exchanger has an aluminum tube through which a refrigerant flows and an aluminum fin for exchanging heat between air outside the tube, and the tube and the fin are joined to each other. ing. Since the hydrophilicity of the fin greatly affects the heat exchange performance of the heat exchanger, a fin having a hydrophilic coating film formed on the surface is often used. For joining the fin and the pipe having such a hydrophilic coating film, a method of mechanically joining the two by expanding the pipe inserted into the hole provided in the fin (patent) Reference 1 and Patent Reference 2).

As a joining method, in addition to the above-described mechanical joining, brazing joining is assumed. However, since a general resin-based or inorganic coating film is altered or decomposed at the heating temperature at the time of brazing, it cannot sufficiently exhibit hydrophilicity after brazing. Further, when flux is used for brazing, the flux action is hindered by the presence of the coating film, and brazing joining may be insufficient. Therefore, when manufacturing a heat exchanger by brazing, the coating film is generally formed after brazing (refer patent document 3). However, in this case, there is a problem that the manufacturing cost increases because a dedicated coating film forming facility is required. In this case, it is difficult to cope with an increase in the size of the heat exchanger.

Therefore, a fin material having a coating film mainly composed of silicate has been proposed as a fin material having a coating film pre-coated before brazing (see Patent Document 4). Further, in the production of a heat exchanger, a method for producing a fin in which a film containing a support such as xylene or a silicon-based binder such as silicone oil is formed before brazing has been proposed (Patent Document 5). reference).

JP-A-4-278189 JP 2012-052747 A JP 2004-347314 A JP 2013-137153 A Special table 2008-508103 gazette

However, fin films pre-coated with conventional coatings and films have insufficient hydrophilic sustainability after brazing and insufficient brazing function. That is, the conventional fin material did not have excellent hydrophilic sustainability and excellent brazing function. Therefore, it is necessary to supply a brazing material separately when manufacturing the heat exchanger using the fin material. As a result, a decrease in manufacturability due to an increase in the manufacturing process and an increase in manufacturing cost due to member procurement are expected. In addition, the pre-coated coating film or coating film adversely affects the brazing joint between the fin using the brazing material and the aluminum tube, and there is a possibility that the joining property is insufficient. Therefore, development of a pre-coated fin material that can maintain a superior hydrophilic sustainability and can produce a heat exchanger that can be joined without using a brazing material and has excellent joining properties between the fin and the aluminum tube. Is desired.

The present invention has been made in view of such a background, and is excellent in the hydrophilic sustainability of the fins, can be joined between the fins and the aluminum pipe without separately supplying a brazing material, and has excellent joining properties. An object of the present invention is to provide a pre-coated fin material capable of producing an exchanger, and a heat exchanger using the pre-coated fin material.

One aspect of the present invention is an aluminum alloy plate;
A coating formed on the surface of the aluminum alloy plate,
The aluminum alloy plate contains Si: 1 to 5% by mass, and the balance has chemical components composed of Al and inevitable impurities,
The pre-coated fin material has a Si content in the coating film of 10 to 300 mg / m ² .

Another aspect of the present invention resides in a heat exchanger having a core portion made of a fin made of the pre-coated fin material and an aluminum tube joined to the fin.

In the pre-coated fin material, the aluminum alloy plate contains Si in the specific range, and the balance has chemical components composed of Al and inevitable impurities. Therefore, for example, by heating at about 600 ° C., a liquid phase is generated from the inside of the aluminum alloy plate and oozes out to the surface, and the liquid phase solidifies during cooling, so that, for example, joining with other aluminum members such as an aluminum tube is possible. It becomes possible. Therefore, it becomes possible to join without separately using a joining member such as a brazing material, and it is possible to ensure a sufficient joining property without using a brazing material. Furthermore, since joining is possible without using a joining member such as a brazing material, it is possible to meet the demand for cost reduction. Moreover, since the components of the aluminum alloy plate itself are used for joining, the performance of the coating film formed on the surface of the aluminum alloy plate by a joining member such as a brazing material is not impaired.

In addition, the coating film in which the Si amount is adjusted as described above is unlikely to deteriorate in coating film performance due to heating or the like. Therefore, the coating film can exhibit excellent hydrophilicity even after heating at the time of joining with another member such as an aluminum tube, and can maintain the initial excellent hydrophilicity for a long period of time. Moreover, a coating film hardly inhibits joining with other aluminum members, such as an aluminum pipe, and a precoat fin material, for example. Therefore, although the said precoat fin material has a coating film, sufficient joining with an aluminum pipe, for example is possible.

Thus, in the pre-coated fin material, the components of the coating film and the aluminum alloy plate are optimized as described above. Therefore, it is possible to manufacture a heat exchanger that is excellent in hydrophilic sustainability of the fins, can join the fins to the aluminum pipe without separately supplying a brazing material, and has excellent joining properties.

Moreover, the said heat exchanger has a core part which consists of the fin which consists of a precoat fin material excellent in the above-mentioned hydrophilic sustainability and joining property, and the aluminum pipe joined to the fin.
Therefore, in the heat exchanger, since fins exhibit excellent hydrophilic sustainability, an increase in ventilation resistance can be suppressed, and good heat exchange performance can be stably exhibited for a long period of time. Further, in the heat exchanger, for example, an aluminum tube and a fin are sufficiently joined, so that the heat exchange performance between the aluminum tube and the fin is improved.

Sectional drawing of the precoat fin material in Example 1. FIG. The perspective view of the core part (specifically minicore) of the heat exchanger in Example 1. FIG. Sectional drawing of the core part (specifically minicore) of the heat exchanger in Example 1. FIG. The expanded sectional view of the fin of the heat exchanger in Example 1. FIG. In Example 1, (a) The fragmentary sectional view of the contact part of the fin and aluminum tube before joining, (b) The fragmentary sectional view of the contact part of the fin and aluminum tube after joining. The front view of the heat exchanger in Example 2. FIG. The perspective view of the principal part of the heat exchanger in Example 3. FIG. The partial expanded sectional view of the contact part vicinity in FIG. FIG. 8 is a cross-sectional view taken along line III-III in FIG.

The pre-coated fin material is used for joining a fin made of the pre-coated fin material and an aluminum tube to obtain a heat exchanger. In the present specification, the “aluminum tube” is a concept including not only a pure aluminum tube but also an aluminum alloy tube. Specifically, A1000 series pure aluminum, A3000 series aluminum alloy, or the like can be used.

The pre-coated fin material has an aluminum alloy plate. The chemical components of the aluminum alloy plate include, for example, Si: 1 to 5% by mass, and the balance is Al and inevitable impurities. When the Si content is less than 1% by mass, a sufficient amount of liquid phase cannot be generated, the liquid phase oozes out and bonding becomes incomplete. From the viewpoint of further improving the bondability, the Si content is preferably 1.5% by mass or more, and more preferably 2% by mass or more. On the other hand, when the Si content exceeds 5% by mass, the amount of Si particles in the aluminum alloy plate is increased, and the amount of liquid phase generated is increased. It becomes difficult to maintain the shape as a material. Moreover, in this case, there is a possibility of adversely affecting hydrophilic sustainability. From the viewpoint of improving hydrophilic sustainability while preventing a decrease in strength, the Si content is preferably 4% by mass or less, and more preferably 3% by mass or less.

In addition to Al, Si and inevitable impurities, the chemical components of the aluminum alloy plate include Fe, Mn, Zn, Mg, Cu, In, Sn, Ti, V, Zr, Cr, Ni, Be, Sr, Bi. Further, at least one element selected from the group consisting of Na, and Ca can be further contained. The chemical components of the aluminum alloy plate include, for example, Si: 1 to 5% by mass, and at least one of Fe: 0.1 to 2% by mass and Mn: 0.1 to 2% by mass, with the balance being Al and inevitable impurities. In this case, the strength as a fin material can be improved.

In addition to the effect of improving the strength by slightly dissolving in the matrix of the aluminum alloy structure, Fe has the effect of dispersing as a crystallized substance and preventing a decrease in strength particularly at high temperatures. When the addition amount of Fe is less than 0.1% by mass, not only the above effects are small, but also high-purity ingots need to be used, resulting in an increase in cost. Moreover, when it exceeds 2 mass%, a coarse intermetallic compound will produce | generate at the time of casting, and a problem will arise in manufacturability. Further, when the fin made of the pre-coated fin material is exposed to a corrosive environment (particularly a corrosive environment in which a liquid flows), the corrosion resistance decreases. Furthermore, since the crystal grains recrystallized by heating at the time of bonding are refined and the grain boundary density increases, the dimensional change increases before and after the bonding. Therefore, the addition amount of Fe is preferably 0.1 to 2% by mass as described above. A more preferable addition amount of Fe is 0.2% by mass to 1% by mass.

Mn forms an Al—Fe—Mn—Si based intermetallic compound together with Fe and Si and acts as dispersion strengthening, or it is important to improve strength by solid solution strengthening by solid solution strengthening in the aluminum matrix. It is an additive element. When the addition amount of Mn is less than 0.1% by mass, the above effect is insufficient, and when it exceeds 2% by mass, a coarse intermetallic compound is produced at the time of casting, causing a problem in manufacturability. Therefore, the amount of Mn added is preferably 0.1 to 2% by mass as described above. A more preferable amount of Mn is 0.3 to 1.5% by mass.

Moreover, the chemical component of the aluminum alloy plate can further contain Zn: 0.05 to 6% by mass. That is, the chemical component of the aluminum alloy plate contains, for example, Si: 1 to 5% by mass, and at least one of Fe: 0.1 to 2% by mass and Mn: 0.1 to 2% by mass, Further, Zn: 0.05 to 6% by mass, the balance being Al and inevitable impurities. In this case, the corrosion resistance of the pre-coated fin material can be improved.

Addition of Zn is effective in improving corrosion resistance due to sacrificial anticorrosive action. Zn is dissolved almost uniformly in the matrix, but when a liquid phase is generated, it dissolves into the liquid phase and the Zn in the liquid phase is concentrated. When the liquid phase oozes out to the surface, the Zn concentration in the portion increases, so that the corrosion resistance is improved by the sacrificial anodic action. Moreover, when manufacturing a heat exchanger using the said precoat fin material, the sacrificial anticorrosion effect | action which prevents an aluminum pipe etc. can also be worked by using a precoat fin material for a fin. When the added amount of Zn exceeds 6% by mass, the corrosion rate increases and the self-corrosion resistance decreases. Further, in order to sufficiently obtain the effect of adding Zn, the amount of Zn added is preferably 0.05% by mass or more. Accordingly, Zn is preferably 0.05 to 6% by mass or less as described above.

Moreover, the chemical component of the aluminum alloy plate can further contain at least one of Mg: 2 mass% or less and Cu: 1.5 mass% or less. That is, the chemical component of the aluminum alloy plate contains, for example, Si: 1 to 5% by mass, and at least one of Fe: 0.1 to 2% by mass and Mn: 0.1 to 2% by mass, Zn: 0.05 to 6% by mass, further containing at least one of Mg: 2% by mass or less and Cu: 1.5% by mass or less, with the balance being Al and inevitable impurities. In this case, the strength of the pre-coated fin material can be further improved.

Mg undergoes age hardening by Mg ₂ Si after bonding heating, and the strength is improved by this age hardening. Thus, Mg is an additive element that exhibits the effect of improving the strength. When the amount of Mg added exceeds 2% by mass, it reacts with the flux to form a high melting point compound, so that the bondability is significantly lowered. Therefore, the amount of Mg added is preferably 2% by mass or less as described above. A more preferable amount of Mg is 0.05% by mass to 2% by mass. In the present invention, not only Mg but also other alloy components include 0 when the amount is less than a predetermined addition amount.

Cu is an additive element that improves the strength by solid solution in the matrix. However, if the amount of Cu added exceeds 1.5%, the corrosion resistance decreases. Therefore, the amount of Cu added is preferably 1.5% by mass or less as described above. A more preferable amount of Cu is 0.05% to 1.5%.

The chemical component of the aluminum alloy plate may further contain at least one of In: 0.3% by mass or less and Sn: 0.3% by mass or less. That is, the chemical component of the aluminum alloy plate contains, for example, Si: 1 to 5% by mass, and at least one of Fe: 0.1 to 2% by mass and Mn: 0.1 to 2% by mass, Zn: 0.05 to 6% by mass, further containing at least one of In: 0.3% by mass or less and Sn: 0.3% by mass or less, with the balance being Al and inevitable impurities. In this case, the deterioration of the corrosion resistance of the precoated fin material can be suppressed.

In and Sn have the effect of exerting a sacrificial anodic action. If the amount of addition exceeds 0.3% by mass, the corrosion rate increases and the self-corrosion resistance decreases. Therefore, the amount of each of these elements added is preferably 0.3% by mass or less as described above. A more preferable addition amount is 0.05 to 0.3% by mass.

The chemical components of the aluminum alloy plate are further Ti: 0.3% by mass or less, V: 0.3% by mass or less, Zr: 0.3% by mass or less, Cr: 0.3% by mass or less, and Ni: 2% by mass. % Or less can be contained. That is, the chemical component of the aluminum alloy plate contains, for example, Si: 1 to 5% by mass, and at least one of Fe: 0.1 to 2% by mass and Mn: 0.1 to 2% by mass, Zn: 0.05 to 6% by mass, Ti: 0.3% by mass or less, V: 0.3% by mass or less, Zr: 0.3% by mass or less, Cr: 0.3% by mass or less And Ni: contains at least one selected from 2% by mass or less, with the balance being Al and inevitable impurities. In this case, the strength as a fin material can be improved.

Ti and V have the effect of preventing the progress of corrosion in the plate thickness direction by being dissolved in a matrix and being dissolved in a matrix to improve the strength. When the added amount exceeds 0.3% by mass, a giant crystallized product is generated, which impairs moldability and corrosion resistance. Therefore, the amount of Ti and V added is preferably 0.3% by mass or less as described above. A more preferable addition amount is 0.05 to 0.3% by mass.

Zr precipitates as an Al—Zr intermetallic compound, and exhibits the effect of improving the strength after bonding by dispersion strengthening. In addition, the Al—Zr-based intermetallic compound acts on the coarsening of crystal grains during heating. When the addition amount exceeds 0.3% by mass, it becomes easy to form a coarse intermetallic compound, and the plastic workability is lowered. Therefore, the amount of Zr added is preferably 0.3% by mass as described above. A more preferable addition amount is 0.05% by mass to 0.3% by mass.

Cr improves strength by solid solution strengthening, and Al—Cr-based intermetallic compounds precipitate, which acts on coarsening of crystal grains after heating. When the addition amount exceeds 0.3% by mass, it becomes easy to form a coarse intermetallic compound, and the plastic workability is lowered. Therefore, the amount of Cr added is preferably 0.3% by mass or less as described above. A more preferable addition amount is 0.05 to 0.3% by mass.

Ni is crystallized or precipitated as an intermetallic compound, and has an effect of improving the strength after bonding by dispersion strengthening. When the addition amount exceeds 2% by mass, it becomes easy to form a coarse intermetallic compound, and the workability is lowered. In addition, the self-corrosion resistance is also reduced. Therefore, the amount of Ni added is preferably 2% by mass or less as described above. A more preferable addition amount is 0.05 to 2% by mass.

The chemical components of the aluminum alloy plate are further Be: 0.1 mass% or less, Sr: 0.1 mass% or less, Bi: 0.1 mass% or less, Na: 0.1 mass% or less, Ca: 0.05 At least 1 sort (s) chosen from the mass% or less can be contained. That is, the chemical component of the aluminum alloy plate contains, for example, Si: 1 to 5% by mass, and at least one of Fe: 0.1 to 2% by mass and Mn: 0.1 to 2% by mass, Zn: 0.05 to 6% by mass, Be: 0.1% by mass or less, Sr: 0.1% by mass or less, Bi: 0.1% by mass or less, Na: 0.1% by mass or less Ca: At least one selected from 0.05% by mass or less, with the balance being Al and inevitable impurities. In this case, the bondability can be further improved by improving the liquid phase characteristics.

More preferable ranges of these elements are Be: 0.0001 to 0.1% by mass, Sr: 0.0001 to 0.1% by mass, Bi: 0.0001 to 0.1% by mass, Na: 0.0001. -0.1 mass%, Ca: 0.0001-0.05 mass%. These trace elements have a small effect when the amount is less than the above-mentioned more preferable specified range, and when the amount exceeds the above-mentioned more preferable specified range, adverse effects such as a decrease in corrosion resistance may occur. In addition, when 1 type, or 2 or more types of Be, Sr, Bi, Na, and Ca are added, it is required that all of the added components are within the above preferable or more preferable component ranges.

Next, a method for producing an aluminum alloy plate will be described. The aluminum alloy plate is cast using a DC (Direct Chill) casting method, and the casting speed of the slab at the time of casting is controlled as follows, for example. Since the casting speed affects the cooling speed, it is preferably 20 to 100 mm / min. When the casting speed is less than 20 mm / min, a sufficient cooling rate cannot be obtained, and crystallized intermetallic compounds such as Si-based intermetallic compounds and Al—Fe—Mn—Si-based intermetallic compounds are coarsened. On the other hand, when it exceeds 100 mm / min, the aluminum material is not sufficiently solidified during casting, and a normal ingot cannot be obtained. More preferably, it is 30 to 80 mm / min. And in order to obtain a desired metal structure, a casting speed can be adjusted according to the composition of the alloy material to manufacture. Although the cooling rate depends on the cross-sectional shape of the slab such as thickness and width, the cooling rate of 0.1 to 2 ° C./second can be achieved at the center of the ingot by setting the casting rate to 20 to 100 mm / min.

The ingot (slab) thickness during DC continuous casting is preferably 600 mm or less. When the slab thickness exceeds 600 mm, a sufficient cooling rate cannot be obtained and the intermetallic compound becomes coarse. A more preferable slab thickness is 500 mm or less.

The slab manufactured by the DC casting method is subjected to a heating process before hot rolling, a hot rolling process, a cold rolling process, and an annealing process. A homogenization treatment may be performed after casting and before hot rolling.

The slab manufactured by the DC casting method is subjected to a heating process before hot rolling after homogenization or without being homogenized. In this heating step, it is preferable that the heating holding temperature is 400 to 570 ° C. and the holding time is about 0 to 15 hours. When holding temperature is less than 400 degreeC, the deformation resistance of the slab in hot rolling is large, and there exists a possibility that a crack may generate | occur | produce. When holding temperature exceeds 570 degreeC, there exists a possibility that melting may arise locally. When the holding time exceeds 15 hours, precipitation of the Al—Fe—Mn—Si intermetallic compound proceeds, the precipitate becomes coarse and the distribution becomes sparse, and the nuclei of the recrystallized grains during bonding heating The frequency of occurrence increases and the crystal grain size decreases. The holding time of 0 hour means that the heating is terminated immediately after reaching the heating holding temperature.

続い Following the heating process, the slab is subjected to a hot rolling process. The hot rolling process includes a hot sparse rolling stage and a hot finish rolling stage. Here, it is assumed that the total rolling reduction in the hot rough rolling stage is 92 to 97%, and each pass of the hot rough rolling includes three or more passes where the rolling reduction is 15% or more.

In the slab manufactured by the DC casting method, a coarse crystallized product is generated in the final solidified part. In the step of forming the plate material, the crystallization product is subjected to shearing by rolling and is divided into small pieces, so that the crystallization product is observed in the form of particles after rolling. The hot rolling process includes a hot rough rolling stage for obtaining a plate having a certain thickness from the slab and a hot finish rolling stage for obtaining a thickness of about several mm. In order to separate the crystallized product, it is preferable to control the rolling reduction in the hot rough rolling stage rolled from the slab. Specifically, in the hot rough rolling stage, the slab thickness is rolled from 300 to 700 mm to about 15 to 40 mm, but the total rolling reduction in the hot rough rolling stage is 92 to 97%, and the hot rough rolling stage By including a pass having a rolling reduction of 15% or more three times or more, a coarse crystallized product can be finely divided. As a result, the Si-based intermetallic compound and the Al—Fe—Mn—Si-based intermetallic compound, which are crystallized substances, can be refined, and an appropriate distribution state can be obtained.

If the total rolling reduction in the hot rough rolling stage is less than 92%, the effect of refining the crystallized product cannot be obtained sufficiently. On the other hand, if it exceeds 97%, the thickness of the slab is substantially increased, and the cooling rate during casting is slowed down, so that the crystallized material is coarsened, and the crystallized material is sufficiently refined even when hot rough rolling is performed. Not done. Further, the reduction rate in each pass in the hot rough rolling stage also affects the distribution of intermetallic compounds, and the crystallized product is divided by increasing the reduction rate in each pass. If the number of passes with a rolling reduction of 15% or more in each pass in the hot rough rolling stage is less than 3 times, the effect of refining the crystallized product is not sufficient. When the reduction ratio is less than 15%, the reduction ratio is not sufficient and the crystallized material is not refined, so that it is not a target. The upper limit of the number of passes at which the rolling reduction is 15% or more is not particularly specified, but it is realistic that the upper limit is about 10 times.

After completion of the hot rolling process, the hot rolled material is subjected to a cold rolling process. The conditions for the cold rolling process are not particularly limited. In the middle of the cold rolling process, an annealing process is provided in which the cold rolled material is sufficiently annealed to have a recrystallized structure. After the annealing step, the rolled material is subjected to final cold rolling to obtain a final thickness. If the processing rate {(plate thickness before processing−plate thickness after processing) / plate thickness before processing} × 100 (%) in the final cold rolling stage is too large, the driving force for recrystallization during joining heating is too high. By increasing the size and reducing the crystal grains, the deformation during the bonding heating increases. Therefore, as described above, the processing amount in the final cold rolling stage is set so that T / To is 1.40 or less. The processing rate in the final cold rolling stage is preferably about 10 to 30%.

Next, the coating film formed on the surface of the aluminum alloy plate will be described.
The coating film may be formed on one side of the aluminum alloy plate or may be formed on both sides. The coating film is formed of, for example, an oxide containing silicon (Si), a composite oxide, or the like, and contains Si. The amount of Si in the coating film is 10 to 300 mg / m ² . When the amount of Si is less than 10 mg / m ² , hydrophilic sustainability may be reduced. From the viewpoint of further suppressing the decrease in hydrophilic durability, the amount of Si in the coating film is more preferably 100 mg / m ² or more. On the other hand, when the amount of Si exceeds 300 mg / m ² , the bondability may be impaired by the coating film. In addition, Si amount is the amount per one side of the coating film. Further, when the Si amount in the coating film is 10 to 300 mg / m ² , the adhesion amount of the coating film is preferably 20 to 800 mg / m ² .

The coating film preferably contains at least one of silicate and amorphous silica. In this case, the hydrophilic durability of the coating film is further improved. From the viewpoint of further improving hydrophilic sustainability, the coating film more preferably contains at least silicate. Silicate is, for example, sodium silicate or lithium silicate. The coating film containing a silicate can be formed by coating an aqueous solution containing a silicate such as water glass on the surface of an aluminum alloy plate and drying it. From the viewpoint of further improving the hydrophilic sustainability, the silicate is more preferably derived from water glass.

Further, as the amorphous silica, for example, there is an aggregate formed by drying amorphous colloidal silica, and from the viewpoint that hydrophilic sustainability can be further improved, amorphous silica is derived from amorphous colloidal silica. It is preferable. The coating film containing amorphous silica can be formed by coating amorphous colloidal silica on the surface of an aluminum alloy plate and drying. Also, a mixture of amorphous colloidal silica and an aqueous solution containing silicate is applied to the surface of the aluminum alloy plate and dried to form a coating film containing amorphous silica and silicate. be able to.

The coating film can further contain a fluoride flux. The fluoride flux content may be zero. The content of the fluoride flux is preferably 0 or more and 5000 mg / m ² or less. In this case, the flux effect can be obtained and the hydrophilic sustainability can be further improved. If the content of the fluoride flux is too small, the effect of adding the flux may not be sufficiently obtained. Therefore, the content of the fluoride flux is more preferably 40 mg / m ² or more, further preferably 500 mg / m ² or more, and further preferably 1000 mg / m ² or more. On the other hand, when there is too much content of fluoride flux, there exists a possibility that hydrophilic sustainability may fall. From the viewpoint of suppressing a decrease in hydrophilic durability, the content of the fluoride flux is preferably 5000 mg / m ² or less, more preferably 3000 mg / m ² or less, as described above, and 2000 mg / m ^2. More preferably, it is as follows. When the coating film contains fluoride flux in the above range, the coating amount is preferably 50 to 6000 mg / m ² .

As fluoride flux, KAlF ₄ , K ₂ AlF ₅ , K ₂ AlF ₅ .H ₂ O, K ₃ AlF ₆ , AlF ₃ , KZnF ₃ , K ₂ SiF ₆ , Cs ₃ AlF ₆ , CsAlF ₄ .2H ₂ O , Cs ₂ AlF ₅ .H ₂ O, and the like. When the coating film contains a fluoride flux, the coating film may have a Si content of 10 to 300 mg / m ² , and may be formed by a single layer containing a fluoride flux. May be formed of a laminate of a layer having a thickness of 10 to 300 mg / m ² and a layer mainly composed of fluoride flux. Specifically, in the case of a single layer, the coating film is formed of a layer containing, for example, at least one of silicate and amorphous silica and a fluoride flux. In the case of a laminate having a two-layer structure, the coating film is formed of, for example, a layer mainly containing at least one of silicate and amorphous silica and a layer mainly containing fluoride flux.

The coating film can further contain an organic resin. In this case, the coating property at the time of forming the coating film is improved. Moreover, it can prevent that Si components, such as a silicate and an amorphous silica, fall off from a coating film.

The organic resin is preferably made of a water-soluble acrylic resin and / or polyoxyethylene alkylene glycol (PAE). In this case, the organic resin is easily decomposed by heating at the time of bonding, for example, and the organic resin can be lost from the coating film. As a result, since the organic resin in the coating film after bonding decreases, it is possible to prevent the bondability from being inhibited by the organic resin.

Moreover, it is preferable that the pre-coated fin material has a base treatment layer made of a chemical conversion film formed between the aluminum alloy plate and the coating film. In this case, the adhesion between the aluminum alloy plate and the coating film can be improved. The base treatment layer made of the chemical conversion film can be formed by, for example, phosphoric acid chromate treatment, zirconium phosphate treatment, boehmite treatment, or the like. The ground treatment layer only needs to improve the adhesion between the aluminum alloy plate and the coating film, and may be formed by other treatments.

In the heat exchanger, shapes such as insertion fins and corrugated fins can be adopted as the fins made of the pre-coated fin material. In order to improve the heat exchange performance, the fin material may have a slit.

As the shape of the aluminum tube, a round tube or a flat tube can be adopted. An inner column that divides the interior into a plurality of passages may be formed in the pipe. More specifically, for example, a flat multi-hole tube can be adopted as the aluminum tube.

Next, a method of joining the fin made of the pre-coated fin material and the aluminum tube will be described. In joining, the joining ability exhibited by the aluminum alloy plate itself of the fin material can be utilized without using a brazing material. Considering the use of heat exchangers as fins, it is desirable to avoid deformation of the fin material itself, and for this reason, the bonding heating conditions can be managed. Specifically, it is above the solidus temperature where the liquid phase is generated inside the aluminum alloy plate and below the liquidus temperature, and the liquid phase is generated on the aluminum alloy plate, the strength is lowered and the shape is maintained. Heating is performed for a time required for bonding at a temperature below the temperature at which it cannot be performed.

As more specific heating conditions, the ratio of the mass of the liquid phase generated in the aluminum alloy plate to the total mass of the aluminum alloy plate (hereinafter referred to as “liquid phase ratio”) exceeds 0% and is 35% or less. It is preferable to join at a temperature at which Since the bonding cannot be performed unless the liquid phase is generated, the liquid phase ratio needs to be more than 0%. However, if the liquid phase is small, joining may be difficult, so the liquid phase ratio is preferably 5% or more. If the liquid phase ratio exceeds 35%, the amount of the liquid phase to be generated is too large, and the aluminum alloy plate may be greatly deformed during bonding heating, and the shape may not be maintained. A more preferable liquid phase ratio is 5 to 30%, and a further preferable liquid phase ratio is 10 to 20%.

Further, in order to sufficiently fill the liquid phase between the fin and the aluminum tube, it is preferable to consider the filling time, and the time during which the liquid phase ratio is 5% or more is 30 seconds or more and 3600 seconds or less. Is preferred. More preferably, the time when the liquid phase ratio is 5% or more is 60 seconds or more and 1800 seconds or less, whereby further sufficient filling is performed and reliable bonding is performed. If the time during which the liquid phase ratio is 5% or more is less than 30 seconds, the joint may not be sufficiently filled with the liquid phase. On the other hand, if it exceeds 3600 seconds, the deformation of the aluminum alloy plate may proceed. In the method of joining the fin and the aluminum tube, the liquid phase moves only in the very vicinity of the joint, so that the time required for filling does not depend on the size of the joint.

As a specific example of the heating conditions, it is preferable that the bonding temperature is 580 ° C. to 640 ° C., and the holding time at the bonding temperature is about 0 to 10 minutes. Here, 0 minutes means that the cooling is started as soon as the temperature of the member reaches a predetermined joining temperature. The holding time is more preferably 30 seconds to 5 minutes. On the other hand, regarding the bonding temperature, for example, when the Si content of the aluminum alloy plate is about 1 to 1.5%, it is desirable to increase the bonding heating temperature to 610 to 640 ° C. Conversely, when the Si content of the aluminum alloy plate is about 4 to 5%, the bonding heating temperature is preferably set to a low value of 580 to 590 ° C. Moreover, in order to make the metal structure of a junction part into a suitable state, you may adjust a heating condition according to a composition.

Note that it is extremely difficult to measure the actual liquid phase rate during heating. Therefore, the liquid phase ratio can be usually obtained from the alloy composition and the highest temperature by the lever rule using an equilibrium diagram. In an alloy system whose phase diagram is already known, the phase diagram can be used to determine the liquid phase ratio using the principle of leverage. On the other hand, for an alloy system whose equilibrium diagram is not disclosed, the liquid phase ratio can be obtained using equilibrium calculation diagram software. The equilibrium calculation phase diagram software incorporates a technique for determining the liquid phase ratio based on the lever principle using the alloy composition and temperature. Equilibrium calculation state diagram software includes Thermo-Calc; Thermo-Calc Software AB, etc. Even in an alloy system whose equilibrium phase diagram has been clarified, calculating the liquid phase rate using the equilibrium calculation phase diagram software is the same as the result of calculating the liquid phase rate using this principle from the equilibrium phase diagram. As a result, equilibrium calculation state diagram software may be used for simplification.

Further, the heating atmosphere in the heat treatment is preferably a non-oxidizing atmosphere substituted with nitrogen, argon or the like. In addition, better bondability can be obtained by using a non-corrosive flux. Furthermore, it is also possible to join by heating in vacuum or reduced pressure.

Examples of the non-corrosive flux coating method include a method in which fins and an aluminum tube are assembled and then sprinkled with flux powder, a method in which flux powder is suspended in water and sprayed, and the like. In the case of coating the material in advance, the adhesion of the coating can be improved by mixing and applying a binder such as an acrylic resin to the flux powder. Non-corrosive fluxes used to obtain normal flux functions include KAlF ₄ , K ₂ AlF ₅ , K ₂ AlF ₅ .H ₂ O, K ₃ AlF ₆ , AlF ₃ , KZnF ₃ , K ₂ SiF ₆ , Examples thereof include Cs ₃ AlF ₆ , CsAlF ₄ .2H ₂ O, and Cs ₂ AlF ₅ .H ₂ O.

Since the aluminum alloy plate has the above composition, the fin made of the pre-coated fin material can achieve good bonding by the above heat treatment and control of the heating atmosphere. However, since the fin is thin, the shape may not be maintained if the stress generated inside is too high. In particular, when the liquid phase ratio at the time of joining becomes large, it is possible to maintain a good shape by keeping the stress generated in the fin at a relatively small stress. Thus, when it is preferable to consider the stress in the fin, when the maximum value of the stress generated in the fin is P (kPa) and the liquid phase rate is V (%), P ≦ 460-12V If the conditions are met, a very stable joint can be obtained. The value indicated by the right side (460-12V) of this equation is the critical stress, and if a stress exceeding this value is applied to the fin, there is a possibility that a large deformation will occur. The stress generated in the fin is obtained from the shape and load. For example, it can be calculated using a structural calculation program or the like.

The heat exchanger has a core portion made of a fin made of a pre-coated fin material and an aluminum tube joined to the fin. Although the specific example of a heat exchanger is demonstrated using drawing in the below-mentioned Example, a heat exchanger is manufactured by attaching a header, a side support, an entrance / exit pipe | tube, etc. to a core part.

The heat exchanger can be used for an air conditioner and a refrigerator, for example. It can also be used for automobile condensers, evaporators, radiators, heaters, intercoolers, oil coolers, and the like. Furthermore, it can also be used for a cooling device for cooling a heating element such as an IGBT (Insulated Gate Bipolar Transistor) provided in an inverter unit for controlling a drive motor of a hybrid vehicle or an electric vehicle.

(Example 1)
This example is an example in which a plurality of precoated fin materials according to examples and comparative examples of the present invention are manufactured and their performance is compared. In this example, as shown in Tables 1 to 7 described later, a plurality of pre-coated fin materials (sample E1-1 to sample E7-5, sample C1-1 to sample) having different compositions of aluminum alloy plates and coating compositions are used. C7-5) is prepared. And using each of these precoat fin materials, the core part for heat exchangers is produced, and hydrophilicity sustainability and bondability are compared and evaluated. In this example, a test mini-core is manufactured as the core portion.

As illustrated in FIG. 1, the pre-coated fin material 1 has an aluminum alloy plate 11 and a coating film 12 formed on the surface thereof. The aluminum alloy plate 11 contains additional components (elements) shown in the table below, and the balance has chemical components composed of Al and inevitable impurities. The coating film 12 contains Si derived from lithium silicate at a content shown in the table below, and further contains a water-soluble acrylic resin in such an amount that the coating property can be improved. Moreover, in a part of the precoat fin material produced in this example, the coating film further contains a flux in an amount shown in a table described later. The coating film is formed on both surfaces of the aluminum alloy plate.

As shown in FIGS. 2 and 3, the mini-core 2 has a fin 3 made of the pre-coated fin material 1 and an aluminum tube 4, and the corrugated fin 3 is sandwiched between the aluminum tubes 4. In FIG. 2, one of the two aluminum tubes 4 sandwiching the fin 3 is indicated by a broken line in order to clearly show the corrugated shape of the fin 2.

As shown in FIG. 4, the fin 3 is made of a pre-coated fin material 1 formed in a corrugated shape, and includes an aluminum alloy plate 11 and a coating film 12 formed on both surfaces thereof.

2 and 3, the aluminum tube 4 is a flat multi-hole tube made of an aluminum alloy. The aluminum tube 4 has a large number of refrigerant flow paths 411 for circulating the refrigerant. In the mini-core 2, as shown in FIG. 5B, the fin 3 and the aluminum tube 4 are joined, and a fillet 200 is formed at the joint between both.

Hereinafter, a method for manufacturing the mini-core 1 of this example will be described. Specifically, first, an aluminum alloy plate 11 containing additive components shown in each table was prepared. Components other than the additive components shown in each table, that is, the balance is Al and inevitable impurities. Next, a base treatment layer made of a chemical conversion film (not shown) was formed on both surfaces of the aluminum alloy plate 11 by performing a base treatment. As the base treatment, phosphoric acid chromate treatment was performed. The thickness of the base treatment layer is, for example, about 1 μm.

Next, using a bar coater, a predetermined amount of water glass, a water-soluble acrylic resin, and a coating containing KAlF ₄ which is a fluoride flux added as needed is applied on the base treatment layer, and the temperature is 200 ° C. The coating film 12 was formed by drying with (refer FIG. 1). In this way, precoated fin material 1 having coating film 12 containing Si derived from water glass with the contents shown in Tables 1 to 7 on aluminum alloy plate 11 was produced. The coating film 12 was formed on both surfaces of the aluminum alloy plate 11.

The amount of Si in the coating film 12 was measured by fluorescent X-ray analysis. The fluorescent X-ray analysis was performed using a ZSX Primus II manufactured by Rigaku under the conditions of atmosphere: vacuum, tube: Rh, output: 50 kV-60 mA. Quantification of Si in the coating film was performed by a calibration curve method using a standard Si sample.

Next, the pre-coated fin material 1 was processed into a corrugated shape. Thus, a corrugated fin 3 having a coating film 12 formed on the surface of the aluminum alloy plate 11 was obtained (see FIGS. 2 to 4). These fins 3 are respectively used for manufacturing the mini-core 1.

Next, as the aluminum tube 4, a flat multi-hole tube made of 3000 series aluminum alloy was produced by extrusion (see FIGS. 2 and 3). A corrugated fin 3 was sandwiched between two aluminum tubes 4 to produce an assembly (see FIGS. 2 and 3). At this time, as shown in FIG. 5A, each vertex 30 of the corrugated fin 3 and the aluminum tube 4 were brought into contact with each other. Next, the assembly was held in a furnace at a temperature of 600 ° C. in a nitrogen gas atmosphere for 3 minutes, and then cooled to room temperature (25 ° C.). A liquid phase is generated from the inside of the aluminum alloy plate 11 of the fin 3 during heating in the furnace and oozes out to the surface, and the liquid phase solidifies during cooling. By this solidification of the liquid phase, a fillet 200 is formed between the fin 3 and the aluminum tube 4 as illustrated in FIG. In this way, as illustrated in FIGS. 2 and 3, the mini-core 2 in which the fin 3 and the aluminum tube 4 are joined is obtained.

Next, the pre-coated fin material 1 and the mini-core 2 of each sample obtained as described above were evaluated for hydrophilic sustainability, bondability, deformation rate, corrosion resistance, and manufacturability as follows. The results are shown in Tables 1 to 7.

<Hydrophilic sustainability>
The hydrophilic durability was evaluated using the precoated fin material of each sample. Each sample is heated under the assumption of fin bonding performed after the formation of the coating film. Specifically, the pre-coated fin material was heated for 3 minutes in a furnace having a temperature of 600 ° C. in a nitrogen gas atmosphere. Next, the pre-coated fin material was immersed in pure water for 2 minutes and then air-dried for 6 minutes. This cycle of immersion in pure water and air drying was repeated 300 times. Subsequently, the contact angle of the water droplet on the coating film of each test plate was measured. The contact angle was measured using a FACE automatic contact angle meter “CA-Z” manufactured by Kyowa Interface Chemical Co., Ltd. Specifically, a water drop was dropped on the coating film at room temperature, and the contact angle of the water drop after 30 seconds was measured. When the contact angle is less than 10 °, it is evaluated as “A”, when it is 10 ° or more and less than 20 °, it is evaluated as “B”, and when it is 20 ° or more and less than 30 °, it is evaluated as “C”. The case of 30 ° or more was evaluated as “D”.

<Jointability>
The joined portion in each mini-core after joining is cut with a cutter knife, and the value obtained by dividing the joining length L ₁ of the fin by the sum of the lengths L ₂ of the ridges of the fin (100/100) (L ₁ / L ₂ × 100) was defined as a bonding rate (%). The case where the joining rate is 90% or more is evaluated as “A”, the case where the joining rate is 80% or more and less than 90% is evaluated as “B”, and the case where the joining rate is 70% or more and less than 80%. The case was evaluated as “D”, and the case of less than 70% was evaluated as “D”.

<Deformation rate>
The fin height of the mini-core before and after joining was measured and the deformation rate due to fin buckling was also evaluated. That is, the case where the ratio of the fin height change before and after joining to the fin height before joining is 5% or less is evaluated as “A”, and the case where it exceeds 5% and is 10% or less is evaluated as “B”. The case where it exceeded 10% and 15% or less was evaluated as “C”, and the case where it exceeded 15% was evaluated as “D”.

<Corrosion resistance>
A CASS test was conducted for 500 hours to confirm the corrosion state of the fins. In the cross-sectional observation with an optical microscope, the case where the remaining amount of fin is 70% or more is evaluated as “A”, the case where it is 50% or more and less than 70% is evaluated as “B”, and the case where it is 30% or more and less than 50% Was evaluated as “C”, and the case of less than 30% was evaluated as “D”.

<Manufacturability>
When the aluminum alloy was rolled, for example, a case where surface cracking occurred and a good plate material could not be produced was evaluated as “x”, and a case where a good plate material could be produced was evaluated as “◯”. In addition, when the manufacturability was “x”, the other evaluations described above were omitted.

As shown in Table 1, Sample E1-1 to Sample E1-4 are superior in hydrophilic sustainability and have a higher bonding rate than Samples C1-1 to C1-4. Therefore, in the pre-coated fin material 1 having the aluminum alloy plate 11 and the coating film 12, the aluminum alloy plate 11 contains 1 to 5% by mass of Si and the balance has chemical components composed of Al and inevitable impurities. Is preferred. The Si content in the coating film 12 is preferably 10 to 300 mg / m ² . Further, as can be seen by comparing Sample E1-5 and Sample E1-6 with Sample E1-7 and Sample 1-8, the coating film can contain fluoride flux, and the content of fluoride flux By adjusting the pH to 40 to 5000 mg / m ² , the hydrophilic sustainability can be further improved.

As can be seen from Table 2, Samples E2-1 to E2-4, which further contain Fe and Mn in the aluminum alloy plate, had a small deformation rate and better strength as a fin material. As is known from Table 2, in order to improve the strength without impairing manufacturability, the aluminum alloy plate contains 1 to 5% by mass of Si, and Fe: 0.1 to 2% by mass and It is preferable that Mn is contained in an amount of 0.1 to 2% by mass, and the balance has a chemical component consisting of Al and inevitable impurities.

As is known from Table 3, the corrosion resistance of Samples E3-1 and E3-2, which further contained Zn in the aluminum alloy plate, was improved. As is known from Table 3, in order to improve the corrosion resistance, the aluminum alloy plate contains 1 to 5% by mass of Si, Fe: 0.1 to 2% by mass, and Mn: 0.1 to 2% by mass. %, Further containing Zn: 0.05 to 6% by mass, with the balance having a chemical component consisting of Al and inevitable impurities.

As is known from Table 4, the strength and corrosion resistance of Sample E4-1 and Sample E4-2, which further contain at least one of Mg and Cu in the aluminum alloy plate, were further improved. As is known from Table 4, in order to improve strength while suppressing deterioration of corrosion resistance and bondability, the aluminum alloy plate contains 1 to 5% by mass of Si, and Fe: 0.1 to 2% by mass. % And Mn: 0.1 to 2% by mass, Zn: 0.05 to 6% by mass, Mg: 2% by mass or less, and Cu: 1.5% by mass or less It is preferable that the balance has a chemical component composed of Al and inevitable impurities.

As can be seen from Table 5, the corrosion resistance of Sample E5-1 and Sample E5-2, which further contained at least one of In and Sn in the aluminum alloy plate, was further improved. As known from Table 5, in order to further improve the corrosion resistance without impairing manufacturability, the aluminum alloy plate contains 1 to 5% by mass of Si, Fe: 0.1 to 2% by mass, and Mn : 0.1 to 2% by mass, Zn: 0.05 to 6% by mass, and further containing at least one of In: 0.3% by mass or less and Sn: 0.3% by mass or less, It is preferable that the balance has a chemical component composed of Al and inevitable impurities.

As is known from Table 6, Samples E6-1 to E6-5, which contain at least one selected from the group consisting of Ti, V, Zr, Cr, and Ni in the aluminum alloy plate, have a small deformation rate. , The strength was more improved. As is known from Table 6, in order to further improve the strength without impairing manufacturability, the aluminum alloy plate contains 1 to 5% by mass of Si, Fe: 0.1 to 2% by mass and Mn : 0.1 to 2% by mass, Zn: 0.05 to 6% by mass, Ti: 0.3% by mass or less, V: 0.3% by mass or less, Zr: 0.3% by mass % Or less, Cr: 0.3% by mass or less, and Ni: 2% by mass or less are preferably contained, and the balance has a chemical component composed of Al and inevitable impurities.

As is known from Table 7, samples E7-1 to E7-5, which contain at least one selected from the group consisting of Be, Sr, Bi, Na, and Ca in the aluminum alloy plate, have a low deformation rate. The bondability was further improved. As known from Table 6, in order to sufficiently improve the bondability, the aluminum alloy plate contains 1 to 5% by mass of Si, Fe: 0.1 to 2% by mass, and Mn: 0.1%. 2% by mass, Zn: 0.05% by mass to 6% by mass, Be: 0.1% by mass or less, Sr: 0.1% by mass or less, Bi: 0.1% by mass or less, Na : Containing at least one selected from 0.1% by mass or less and Ca: 0.05% by mass or less, with the balance having a chemical component consisting of Al and inevitable impurities.

(Example 2)
Next, the example of the heat exchanger which has a core part using the precoat fin material shown in Example 1 is demonstrated. As shown in FIG. 6, the heat exchanger 5 has a core portion 2 having a number of configurations similar to those of the mini-core of the first embodiment. Specifically, the core portion 2 is formed by alternately laminating a large number of fins 3 made of a corrugated pre-coated fin material 1 and aluminum tubes 4, and the fins 3 and the aluminum tubes 4 are the mini-cores of the first embodiment. They are joined in the same way.

The header 51 is assembled | attached to the both ends of the aluminum pipe 4, and the side plate 52 is assembled | attached to the both ends (outermost side) in the lamination direction of the core part 2. As shown in FIG. In addition, a tank 53 is assembled to the header 51. These header 51, side plate 52, and tank 53 can be joined by brazing, for example.

In the heat exchanger 5, the precoat fin material 1 similar to the samples E1-1 to E7-5 shown in Tables 1 to 7 can be used. That is, the heat exchanger 5 has the core part 2 which consists of the fin 3 which consists of the precoat fin material 1 excellent in the above-mentioned hydrophilic sustainability, joining property, etc., and the aluminum tube 4 joined to the fin 3. Therefore, since the fin 3 exhibits excellent hydrophilic durability, the heat exchanger 5 can suppress an increase in ventilation resistance and can stably exhibit good heat exchange performance for a long period of time. Further, in the heat exchanger 5, for example, the aluminum tube 4 and the fin 3 are sufficiently joined, so that the heat exchange performance between the aluminum tube 4 and the fin 3 is improved.

(Example 3)
This example is an example of a heat exchanger having a configuration in which an aluminum tube made of a flat multi-hole tube is inserted into an assembly hole formed in a fin. As illustrated in FIG. 7, the heat exchanger 6 includes an aluminum tube 7 and fins 8. As illustrated in FIGS. 7 and 9, the fin 8 has an assembly hole 81 into which the aluminum tube 7 is inserted. As illustrated in FIGS. 7 and 8, the aluminum tube 7 is in contact with the fin 8 at the contact portion 61. As illustrated in FIGS. 7 to 9, in the contact portion 61, a fillet 600 is formed between the aluminum tube 7 and the fin 8 to join both.

As illustrated in FIG. 7, the heat exchanger 6 of this example includes a large number of fins 8 arranged at intervals in the plate thickness direction, and a plurality of aluminum tubes 7 extending in the plate thickness direction of the fins 8. And have. The fin 8 has a substantially rectangular shape in plan view as viewed from the thickness direction. The fin 8 consists of the precoat fin material 1 which has the aluminum plate 11 similar to Example 1, and the coating film 12 formed in the both surfaces.

The assembly hole 81 in the fin 8 is a notch 811 provided in the outer peripheral edge portion of the fin 8. The notch 811 extends in the plate width direction from the outer peripheral edge of the fin 8 and has a U shape in plan view. The notch 811 is configured such that the aluminum tube 7 can be press-fitted from an open portion 812 provided at the outer peripheral edge of the fin 8.

7 and 9, the fin 8 has a collar portion 82 protruding from the peripheral edge of the assembly hole 81. Although the height of the color part 82 is not specifically limited, For example, it can be 200 micrometers or more.

7, the aluminum tube 7 is a flat multi-hole tube in which a cross section in the longitudinal direction has an oval shape and a plurality of flow paths 711 are formed therein. The flat multi-hole tube is arranged so that the width direction thereof is parallel to the plate width direction of the fin plate. As illustrated in FIGS. 7 and 8, the aluminum tube 7 made of a flat multi-hole tube has a collar portion 82 at one end 712 in the width direction, that is, a portion where the surface is curved. Abut. One end portion 712 of the aluminum tube 7 and the tip portion 821 of the U-shape of the collar portion 82 constitute a contact portion 61. As illustrated in FIGS. 8 and 9, a fillet 600 is formed in the contact portion 61. The fillet 600 is formed by the liquid phase exuding from the inside of the aluminum alloy plate 1 of the fin 8 to the surface of the fin 8 and solidifying by heating at the time of joining described later.

The heat exchanger 6 of this example can be manufactured as follows, for example. First, the precoat fin material 1 is produced in the same manner as in Example 1, and the fin 8 is produced by a conventional method using this fin material. Then, the plurality of fins 8 are arranged at intervals in the plate thickness direction. Next, an aluminum tube 7 made of a flat multi-hole tube prepared by a conventional method is press-fitted into the assembly hole 81 of the fin 8, and at least one end 712 of the aluminum tube 7 and the tip 821 of the collar portion 82 are brought into contact with each other. Make contact. Thereafter, for example, the substrate is heated at 600 ° C. for 3 minutes in a nitrogen gas atmosphere and then cooled. The liquid phase oozes out from the inside of the aluminum alloy plate of the fin 8 by heating, and the liquid phase is condensed by cooling, whereby the fillet 600 is formed at the contact portion 61. In this way, the heat exchanger 6 having a core portion in which the aluminum tube 7 and the fin 8 are joined and the aluminum tube 7 and the fin 8 are joined can be manufactured. Also in the heat exchanger of this example, there can exist an effect similar to Example 2. FIG.

As mentioned above, although the Example of this invention was described in detail, this invention is not limited to the above-mentioned each Example, A various change is possible within the range which does not impair the meaning of this invention. .

Claims

An aluminum alloy plate,
A coating formed on the surface of the aluminum alloy plate,
The aluminum alloy plate contains Si: 1 to 5% by mass, and the balance has chemical components composed of Al and inevitable impurities,
A pre-coated fin material, wherein the amount of Si in the coating film is 10 to 300 mg / m 2 .
The pre-coated fin material according to claim 1, wherein the coating film contains at least one of silicate and amorphous silica.
The pre-coated fin material according to claim 1 or 2, wherein the coating film contains lithium silicate.
The precoated fin material according to any one of claims 1 to 3, wherein the coating film further contains 40 to 5000 mg / m 2 of a fluoride flux.
The precoated fin material according to any one of claims 1 to 4, wherein the aluminum alloy plate further contains at least one of Fe: 0.1-2 mass% and Mn: 0.1-2 mass%.
The precoated fin material according to any one of claims 1 to 5, wherein the aluminum alloy plate further contains Zn: 0.05 to 6 mass%.
The precoated fin material according to any one of claims 1 to 6, wherein the aluminum alloy plate further contains at least one of Mg: 2 mass% or less and Cu: 1.5 mass% or less.
The precoated fin material according to any one of claims 1 to 7, wherein the aluminum alloy plate further contains at least one of In: 0.3 mass% or less and Sn: 0.3 mass% or less.
The aluminum alloy plate further includes Ti: 0.3 mass% or less, V: 0.3 mass% or less, Zr: 0.3 mass% or less, Cr: 0.3 mass% or less, and Ni: 2 mass% or less. The precoated fin material according to any one of claims 1 to 8, comprising at least one selected from the group consisting of:
The aluminum alloy plate further has Be: 0.1 mass% or less, Sr: 0.1 mass% or less, Bi: 0.1 mass% or less, Na: 0.1 mass% or less, Ca: 0.05 mass% The precoated fin material according to any one of claims 1 to 9, comprising at least one selected from the following.
11. A heat exchanger having a core part composed of a fin made of the pre-coated fin material according to claim 1 and an aluminum pipe joined to the fin.